Start-Up And Operation; Actual Start-Up; Operating Limitations; Temperatures - Carrier 30GTN Service And Troubleshooting Manual

START-UP AND OPERATION

NOTE: Refer to Start-Up Checklist on pages CL-1 to CL-8.
Actual Start-Up —
Actual start-up should be done
only under supervision of a qualified refrigeration
mechanic.
1. Be sure all service valves are open. Units are shipped from
factory with suction, discharge, and liquid line serv-
ice valves closed.
2. Using the Marquee display, set leaving-fluid set point (CSP.1
is Set Point mode under sub-mode COOL). No cooling
range adjustment is necessary.
3. If optional control functions or accessories are being used,
the unit must be properly configured. Refer to Operating
Data section for details.
4. Start chilled fluid pump.
5. Turn ENABLE/OFF/REMOTE CONTACT switch to EN-
ABLE position.
6. Allow unit to operate and confirm that everything is func-
tioning properly. Check to see that leaving fluid tempera-
ture agrees with leaving set point (CSP.1 or CSP.2), or if
reset is used, with the control point (CTPT) in the Run
Status mode under the sub-mode VIEW.

Operating Limitations

TEMPERATURES (See Table 33) — If unit is to be used in
an area with high solar radiation, mounted position should
be such that control box is not exposed to direct solar
radiation. Exposure to direct solar radiation could affect the
temperature switch controlling cooler heaters.
Table 33 — Temperature Limits for Standard Units
TEMPERATURE
Maximum Ambient Temperature
Minimum Ambient Temperature
Maximum Cooler EWT*
Maximum Cooler LWT
Minimum Cooler LWT†
LEGEND
EWT — Entering Fluid (Water) Temperature
LWT — Leaving Fluid (Water) Temperature
*For sustained operation, EWT should not exceed 85 F (29.4 C).
†Unit requires modification below this temperature.
Low-Ambient Operation — If operating temperatures be-
low 0° F (−18 C) are expected, refer to separate installation
instructions for low-ambient operation using accessory Motor-
master III control. Contact your Carrier representative for
details.
NOTE: Wind baffles and brackets must be field-fabricated
for all units using accessory Motormaster III controls to en-
sure proper cooling cycle operation at low-ambient tempera-
tures. See Installation Instructions shipped with the Motor-
master III accessory for more details.
Brine duty application (below 38 F [3.3 C] LCWT)
for chiller normally requires factory modification.
Contact your Carrier representative for applicable LCWT
range for standard water-cooled chiller in a specific
application.

VOLTAGE

Main Power Supply — Minimum and maximum acceptable
supply voltages are listed in the Installation Instructions.
F C
125 52
0 −18
95 35
70 21
38 3.3
65
Unbalanced 3-Phase Supply Voltage — Never operate a mo-
tor where a phase imbalance between phases is greater than
2%. To determine percent voltage imbalance:
% Voltage Imbalance = 100 x
The maximum voltage deviation is the largest difference
between a voltage measurement across 2 legs and the aver-
age across all 3 legs.
Example: Supply voltage is 240-3-60.
AB = 243 v
BC = 236 v
AC = 238 v
1. Determine average voltage:
243 + 236 + 238
Average voltage =
717
=
3
= 239 v
2. Determine maximum deviation from average voltage:
(AB) 243 − 239 = 4 v
(BC) 239 − 236 = 3 v
(AC) 239 − 238 = 1 v
Maximum deviation is 4 v.
3. Determine percent voltage imbalance:
% Voltage Imbalance = 100 x
= 1.7%
This voltage imbalance is satisfactory as it is below the
maximum allowable of 2%.
IMPORTANT: If the supply voltage phase imbalance
is more than 2%, contact your local electric utility com-
pany immediately. Do not operate unit until imbalance
condition is corrected.
Control Circuit Power — Electronic control includes logic
to detect low control circuit voltage. Acceptable voltage ranges
are shown in the Installation Instructions.
MINIMUM FLUID LOOP VOLUME — To obtain proper
temperature control, loop fluid volume must be at least
3 gallons per ton (3.25 L per kW) of chiller nominal capac-
ity for air conditioning and at least 6 gallons per ton (6.5 L
per kW) for process applications or systems that must op-
erate at low ambient temperatures (below 32 F [0° C]).
Refer to application information in Product Data literature
for details.
FLOW RATE REQUIREMENTS — Standard chillers should
be applied with nominal flow rates approximating those listed
in Table 34. Higher or lower flow rates are permissible to
obtain lower or higher temperature rises. Minimum flow rates
must be exceeded to assure turbulent flow and proper heat
transfer in the cooler.
Operation below minimum flow rate could subject tubes
to frost pinching in tube sheet, resulting in failure of
cooler.
max voltage deviation
from avg voltage
average voltage
3
4
239